The present invention relates generally to a pumping valve and, in particular, to a pumping valve for pumping viscous fluid, such as cream, at atmospheric pressure from a fluid-holding container.
In the past, viscous fluids were removed from fluid-holding containers in a number of different ways. In one prior art system, the viscous fluid was maintained in a container under pressure and a simple control valve was mounted on the container. Upon opening of the valve, the pressurized fluid, e.g., cream, flowed out. However, installation of such a valve is expensive, since it required pressurizing equipment as well as necessary safety equipment usually associated with materials under pressure.
In another type of system, a pumping valve has been used. In this valve, the spout is mounted on the valve plunger and is movable with this valve plunger during the pumping action. As a result, spillage takes place since it is difficult to align the moving spout with the container.
A substantial improvement was achieved with the valve of my prior U.S. Pat. No. 4,953,758. The valve disclosed in this patent permitted pumping fluids at atmospheric pressure from a fluid-holding container with minimal or no spillage. The valve of this patent is easy to operate.
The valve disclosed in my U.S. Pat. No. 4,953,758, comprises a valve body having a valve chamber and a plunger connected to a piston that is slidably received in the valve chamber. The plunger and piston are biased by a spring toward the top of the chamber. A flexible seal is provided on the piston and is biased to a position in which it seals an exit passage of the valve. A spout is connected by a channel to the top of the chamber. A one-way check valve is provided in the valve chamber to prevent flow of fluid outwardly through the inlet opening. The depression of the plunger causes movement of the piston downward through the chamber. This causes fluid in the chamber to press down on a one-way check valve at the bottom of the chamber which prevents fluid from flowing out of the chamber and back into the container. When the check valve prevents fluid from leaving the chamber, the movement of the piston causes sufficient pressure on the flexible seal to cause it to open so that fluid below the seal flows past the seal and into the portion of the valve chamber above the seal. The release of the plunger causes movement of the plunger upward to its initial position due to the bias spring. During this upward movement the fluid is pumped out of the valve through the channel and spout. Additional fluid also enters into the bottom portion of the valve chamber from the fluid-holding container due to the vacuum created by the movement of the piston.
The valve of my U.S. Pat. No. 4,953,758, while performing quite satisfactory, is relatively complex in manufacture and assembly because it has a relatively large number of parts.